1. Technical Field of the Invention
The present invention is directed to a head lamp for a vehicle. More particularly, the present invention relates to an aiming and a leveling mechanism which are independently provided for aiming and leveling a vehicle head lamp.
2. Description of the Background Art
A vehicle head lamp has an aiming mechanism for conducting an aiming adjustment by which an extending direction of an optical axis with respect to a vehicle body is adjusted upon completion of manufacturing a vehicle or at an official check-out of a vehicle. In addition, the head lamp has a leveling mechanism for conducting a leveling adjustment by which an extending direction of an optical axis is adjusted according to a weight of a load carried by the vehicle and also according to a position of the load on the vehicle.
FIGS. 6 and 7 show a conventional example of the above discussed vehicle head lamp.
The head lamp "a" for vehicle use is composed of a light source bulb "f" attached to a reflector "e" arranged in a lighting device space "d" which is formed by a container-shaped lamp body "b", the front portion of which is open, and a lens "c" which covers the opening of the lamp body "b".
At the rear of the lamp body "b", an insertion hole "g" is formed.
At the rear of the reflector "e", a light bulb attaching hole "h" is formed. The light source bulb "f" is provided in the light bulb attaching hole "h". The light source bulb "f" has a base section "i" which includes a flange section "j", a section "k" to be attached to the reflect "e", which is located on the front side of the flange section "j", and a cover attaching section "l" located at the rear of the flange section "j". The section "k" of the light source bulb "f", is set in the light bulb attaching hole "h".
A rubber cover "m" has an annular profile, and an inner circumferential edge "n" of the rubber cover "m" is attached to the cover attaching section "l" of the light source bulb "f". An outer circumferential edge "o" of the rubber cover "m" is attached to an opening edge of an insertion hole "g" of the lamp body "b". As described above, since the inner circumferential edge "n" of the rubber cover "m" is attached to the cover attaching section "l" and at the same time the outer circumferential edge "o" is attached to the opening edge of the insertion hole "g", the insertion hole "g" is covered with the rubber cover "m". Therefore, the rubber cover "m" prevents entrance of water and dust from the insertion hole "g" into the lighting device space "d".
On the back of the reflector "e", there are provided two support sections "p", "p" which are protruded and transversely separated from each other, wherein only one support section is shown in FIG. 6. At a lower end portion of the reflector "e", there is provided a ball bearing section "r" which is located at a position under the left support section "p".
An aiming screw "s", "s" is composed of a head section "t", "t", and a screw shaft section "u", "u". Each screw shaft section "u", "u" is inserted into the lamp body "b" from the back and screwed to each screw hole "q", "q" of each support section "p", "p" formed in the reflector "e".
A leveling actuator "v" is arranged so that a connecting shaft "x" is protruded from a main body "w" and a spherical section "y" is integrally formed at an end of the connecting shaft "x". The leveling actuator "v" is operated so that the connecting shaft "x" is moved in the longitudinal direction by an automatic operation or a remote operation.
When the main body "w" of the leveling actuator "v" is attached from the outside to a lower end section of the lamp body "b", the spherical section "y" is connected to the ball bearing section "r" formed in the reflector "e". Accordingly, as shown in FIG. 6, a portion of the leveling actuator "v" is protruded backward from the lamp body "b".
As described above, the reflector "e" is supported by the lamp body "b" at three points A, B and C via the aiming screws "s", "s" and the leveling actuator "v", as shown in FIG. 7.
Aiming adjustment is conducted when the head sections "t", "t" of the aiming screws "s", "s" are rotated.
For example, when the head section "t" of the right aiming screw "s" is rotated, the screw shaft "u" is screwed into the screw hole "q" of the reflector "e" according to the rotation of the screw shaft "u", or alternatively the screw shaft "u" is screwed back in the screw hole "q" of the reflector "e". Due to the foregoing, an interval between the reflector "e" and the lamp body "b" at support point A is changed. Therefore, the reflector "e" is tilted around a tilting axis connecting the two rest support points B and C.
Leveling adjustment is conducted in such a manner that the connecting shaft "x" of the leveling actuator "v" is moved in the longitudinal direction.
When the connecting shaft "x" is moved in the longitudinal direction, an interval between the reflector "e" and the lamp body "b" at support point C is changed. Therefore, the reflector "e" is tilted around a tilting axis connecting the two rest support points A and B.
With this arrangement, the various devices and mechanisms for aiming and leveling the lamp are provided in a limited space.
In the above conventional head lamp "a" for vehicle use, the leveling actuator "v" is attached to the lamp body "b" so that the reflector "e" can be tilted with respect to the lamp body "b" when leveling adjustment is conducted. Therefore, a portion of the leveling actuator "v" is protruded backward from the lamp body "b". Consequently, since the leveling actuator "v" is protruded, the protruding portion tends to interfere with other devices and mechanisms. For the above reasons, depending upon a type of vehicle, it is impossible to ensure a sufficiently large space for arranging the head light "a" for vehicle use to which the actuator "v" is attached. In this case, it becomes necessary to change an attaching position of the leveling actuator "v" with respect to the head lamp "a" for vehicle use. That is, it is necessary to give consideration to an attaching position of the leveling actuator "v" for each type of vehicle.
When the attaching position of the leveling actuator "v" with respect to the head lamp "a" for vehicle use is changed, other support points A and B must be changed according to the change in the attaching position of the leveling actuator "v". As a result, a forming position of each support point with respect to the head lamp "a" for vehicle use is restricted.